Numerical analysis on cavitation effects in submerged water jet added with turbulent drag-reducing additives of CTAC

Abstract

In this paper the cavitation phenomenon and bubble collapse in submerged water jet added with CTAC were studied. The cavitation simulation was based on an improved cavitation model established by introducing coefficients into traditional cavitation model. The coefficients were obtained by fitting the numerical solutions of Rayleigh-Plesset equation in which the viscosity term and surface tension term were not neglected. Cross model was also employed to express the shear-thinning character of the surfactant solution. Simulation results show that the whole cavitation intensity decreased but the scale of cavitation region increased in drag-reducer solution. The submerged water jet added with drag-reducer was less dispersed and the stagnation pressure near the wall was significantly improved. Simulation results of the bubble collapse process show that the bubble collapsed more slowly in drag-reducer solution in comparison with that in pure water. The two pressure peaks near the wall during the collapse process appeared later in drag-reducer solution and the maximum value of the pressure generated in drag-reducer solution was less than that in pure water.